The present invention relates to halogenated hydantoin products which may be used to produce low dust powders, granules, briquettes, tablets, and other forms by mechanical compaction, and casting from a melt. The present halogenated products also may be in the form of castings, flakes and products made by treating inert carriers with the halogenated hydantoins in a melt condition. More specifically, the present invention relates to halogenated ethylhydantoins (hereinafter referred to as ("HEH") either as sole constituent or in admixture with a halogenated dimethylhydantoin (hereinafter referred to as "halo DMH") so as to produce the product forms enumerated above. As used herein, "HEH" or halogenated ethylhydantoin refers to compounds of the formula ##STR2## wherein R is methyl or ethyl and X.sub.1 and X.sub.2 which may be the same or different are chlorine or bromine. The present invention also contemplates utilizing the HEH in admixture with halo DMH, an active chlorine compound and/or an inert carrier in an amount sufficient to produce the desired end product, e.g. powders, granules, flakes, compacted forms, cast forms, etc.
A distinct need presently exists in bleaching, dishwashing, toilet bowl disinfection and water treatment applications (e.g. cooling water treatment, spa and swimming pool disinfection) for halogenated hydantoins in the form of dust-free powders, granules and shaped forms of high integrity. As used herein, the term "high integrity " is meant to refer to solid products having a predetermined shape (e.g. tablets, granules, flakes, briquettes or the like) which are hard, shape-retentive structures and which, for all intents and purposes, are dust-free. A need for such dust-free forms of halogenated hydantoins exists particularly in light of enviromental and safety considerations. Halogen donor compounds are irritating in nature. If such products exhibit a large amout of dusting, they are undesirable for use in the home as well as in industrial environments, e.g. for bleaching or dishwashing purposes. Additonally, a high dusting product tends to intensify the halogen odor normally associated with halogen donor compounds. Such a halogen odor can, in and of itself, be most irritating, and should be avoided.
Halogenated derivatives of dimethylhydantoin (e.g. 1,3-dibromo-5, 5-dimethylhydantoin; 1-bromo-3-chloro-5,5-dimethylhydantoin and 1,3-dichloro-5,5-dimethylhydantoin) are halogen donors typically utilized for various purposes. Thus, 1-bromo-3-chloro-5,5-dimethylhydantoin used for swimming pool sanitizers, whle 1,3dichloro-5,5-dimethylhydantoin has been used successfully for bleaching (see Kirk-Othmer, Encyclopedia of Chemical Technology, Volume 12, pp. 704-705, Wiley Interscience (1980); and U.S. Pat. No. 2,779,764 to Patterson). However, such halogenated derivatives of dimethylhydantoin are fine, dusty powders which are difficult to compact into solid forms of high integrity or to granulate. Compaction of 1,3dichloro-5,5-dimethylhydantoin has been proposed in U.S. Pat. No. 4,242,216 to Daugherty et al, the entire disclosure of which is incorporated herein by reference. In practice, however, it has been found that compaction of 1.3-dichloro-5,5-dimethylhydantoin without binders or additives fails to produce solid forms of high integrity which are commercially desirable and alleviate the dusting problems normally attributable to such solid, physically unstable forms thereof.
Typically, when it is desired to produce commercially acceptable forms of a halogenated dimethylhydantoin, a binder of certain polyvalent metallic cations, for example, those of aluminum, zinc, tin, iron, chromium, magnesium and silicon, is utilized to "cement" the halo DMH into a useable form (see, e.g. U.S. Pat. No. 3,412,021 to Patterson). However, use of such binders necessarily increases the cost of the halogenated hydantoin product, whch cost is passed onto the ultimate consumer. Moreover, such "binders" do not alleviate the dust problem to the degree now realized by the present invention nor provide durable forms or shapes without the use of additives by simple compaction in the dry state.
Problems also exist when attempting to produce solid halo DMH products blended with other materials by high temperature and melt techniques. Such techniques are not feasible with halo DMH due to the high melting ranges of the materials which are relatively close to the decomposition temperatures of the materials as noted in Table 1 below.
TABLE 1 ______________________________________ Melting Point and Decomposition Properties Halogenated DMH Melting Decomposition Range .degree.C. Temperature .degree.C..sup.a ______________________________________ 1. 1,3-Dibromo-5,5- 177-184 186.sup.b .sup. dimethylhydantoin 2. 1-Bromo-3-chloro-5,5- 158-165 160.sup.c .sup. dimethylhydantoin ______________________________________ .sup.a Initiation of an exothermic decomposition when a 3 gram sample is placed in a test tube immersed in an oil bath and heated at a rate of 1-3.degree. C./min. .sup.b vapor forms at 160.degree. C. .sup.c vapor forms at 156.degree. C.
Thus, the narrow temperature range between melting and decomposition of halo DMH derivatives renders such compounds unsuitable for producing commercially acceptable products utilizing techniques involving high temperatures.
Accordingly, it is a primary object of the present invention to provide a method of producing halogen donating hydantoin compounds in the form of low dusting powders or granules, thereby minimizing the irritation normally associated with active halogen compounds.
It is yet a further object of the present invention to provide halogenated hydantoins which can easily be handled by the consumer, both industrial and domestic, with little or no risk of eye, skin and respiratory irritation.
Still yet another object of the present invention is to provide halogenated hydantoins which can readily and easily be shaped into a solid product form having high integrity.
These and other advantageous aspects of the present invention will become more clear to the reader after careful consideration is given the description thereof which follows together with the accompanying examples.